1. Technical Field
The invention relates to light emitting diode (LED) headlamp lighting systems for use in vehicles.
2. Background Art
It is known in the art to provide passenger vehicles with projector headlamp systems. Most projector headlamp systems in current production combine a halogen or High Intensity Discharge (HID) source with a reflector, a lens, a cutoff shield to control the beam pattern, and a transparent cover that protects working parts and enhances appearance.
Active vehicle headlight systems including Steerable or Advanced Front-Lighting and Adaptive Front Lighting Systems (AFS) are known in the art. AFS systems rotate the headlamp projector around its vertical axis to allow steering of the light beam as the vehicle corners. Some automobiles include headlamp systems mechanically integrated with the steering mechanism so the lights follow the movement of the front wheels. Headlamp leveling systems are also known in the art. Headlamp leveling systems rotate the projector around its horizontal axis to adjust the beam pattern for variations in vehicle trim height due to loading. When combining AFS and leveling systems, a gimbal mount may be used to allow two-axis rotation of the projector.
Actuated headlamp systems provide headlamp beam illumination as a car is turned and for a variety of driving conditions. Further, beam height adjustment has been used to compensate headlamp illumination for rear seat occupancy or vehicle loading. The aim of the headlamp beam is lowered as the rear of the vehicle is loaded with passengers and cargo. Usually such adjustment is controlled through an internal, typically wheeled, adjustment. Automatic self-leveling has become increasingly common as light sources have become brighter and the potential hazards of glare to other drivers have increased.
Light emitting diode (LED) headlamps and tail lamps are used in vehicles. LED headlamps consume less energy that halogen bulbs or HID lamps, and have a longer lifetime before replacement.